Principle

Performing this experiment is not difficult and it can be
carried out in daylight as any light interference is shielded by
the tube.

Benefits


Specified for the requirements of the german final secondary-school examinations

Especially for secondary schools

Quantum and wave optics in a student experiment



Tasks

When is an LED a receiver? A light emitting diode or LED is an
electronic semiconductor component. If a current flows through the
LED in the conduction direction it emits light. Physically,
semiconductors are characterised by a band gap, i.e. an
energetically forbidden zone for electrons. This energy gap between
the valence band and the conducting band essentially determines the
electrical and optical properties. E.g. a photon whose energy is
less than the band gap energy of the semiconductor cannot create an
electron-hole pair. In this experiment you will determine the size
of the band gaps of the LED relative to one other.